Means for changing the frequency in combined wireless and television sets



Dec. 23, 1958 H. MEGARD 2,8 5,

MEANS FOR CHANGI THE FREQUENCY IN COMBINED ISION SETS NG WIRELESS AND TELEV 2 Sheets Sheet 1 Filed 001:. 13. 1954 .hv Henry M54674 E 5 4; 4r 7 ABM way Dec. 23, 1958 H. MEGARD 2,855,987

MEANS FOR CHANGING THE FREQUENCY IN COMBINED WIRELESS AND TELEVISION SETS Filed 001:. 13, 1954 2 Sheets-Sheet 2 jwvowf-n- H W2 48 I'd was too low to allow its use FOR CHANGHNG THE FREQUENCY IN COMBINED WIRELESS AND TELEVISION SETS Henry Mgard, Geneva,

Switzerland, assignor to Sautier & Jaeger, Geneva,

Switzerland, a Swiss firm Application October 13, 1954, Serial'No. 462,069

Claims priority, application Switzerland October 16, 1953 8 Claims. (Cl. 178-53) of incoming television waves. a considerable rise in the level that it may serve for the heterodyning both of broadcast radio and television waves. The fundamental frequency may serve for instance for heterodyning broadcast radio frequencies in the low, med1um and high frequency bands serves for heterodyning the band of frequencies ranging between 41 and 68 megacycles used for television frequencies or again for the heterodyning of intermediate frequencies ranging between 82 and I36 megacycles.

Heterodyning is a well-known method consisting in producing upper and lower beats between the local oscillator the amplitude of oscillation is sufficient to reach a value.

at least equal to the biasing of the electrode receiving the-high frequency, divided by V? However, when it fundamental wave,

On the other hand, in certain particular cases of use of the fundamental wavelength, chiefly in the case where the oscillation is injected on the same control grid as the incoming frequency, there may be a risk of the local frequency being shifted by the circuit carrying the incom ing frequency. This risk is all the greater when it'is necessary to cover a continuous range of frequencies.

In order to obtain a rational use of such arrangements, it is, therefore, necessary to bring the multiple harmonics to be used substantially to the same level as the fundamental frequency and to provide an optimum separation between the oscillating and mixing circuits.

My invention has for satisfying such conditions. change of frequency in a vision set, heterodyning through upper or lower beats and multiplication of frequency between a local oscillation and the incoming signal the frequency of which is to be converted, this being obtained by resorting to a frequency transformer and mixer with a view to producing the intermediate frequency for the audio and video signals used in television sets.

According to a further object of my invention, there is inserted between the local oscillator and the mixer an To this end, I provide for the combined wireless and teleits object to design means for is desired to use, in addition to the aperiodic bufler stage including an electronic tube of the control,

which the main electrodes, to wit the cathode,

grid and the anode, are designed andbiased so as to multiply the fundamental frequency of the local oscillation.

My invention includes, for producing a change of two thermionic oscillating the modulating grids are energized by the oscillations fed. by a local electronic oscillator tube system and it ischaracterized by the fact that the anode of such a local oscillating tube is connected with the first control grid of at least one separate buffer tube including a first group of electrodes adjusted so as to double the frequency of the local oscillations and a second group. of electrodes, the control grid in which is coupled with the anode of the first group and is fed, on the other hand, by the amplified incoming signals transmitted by a high frequency stage of a chain reserved for television purposes or otherwise, whereby this second group of electrodes serves as a mixer located ahead of an intermediate frequency television chain.

I have illustrated by way drawings two preferred embodiments of an arrangement according: tomy invention. In said drawings:

- Fig. l isa wiring diagram of the connections of aziirst embodiment; Fig. 2 is a graph relating tothe doubling of the fundamental frequency;

Fig. 3 is a wiring diagram of asecond embodiment of an arrangement according to my invention.

In the example illustrated in Fig. l, the high frequency radio signals transmitted by a broadcasting station are applied after amplification to the control grid g-I of a tube L-l forming an oscillating and modulating tube, the

modulating grid gm of which is connected with the con-.

spectively to the intermediate frequency of the sound television signal and to that of the sound of the broadcast,

I waves, as fed by the anode 41-1.

according to a method which produces a The second transformer inserted in the circuit of the anode a-l is tuned to a frequency of 473 kilocycles and may be short-circuited by a. Wireless and'television switch RV which serves also for the short-circuiting of the transformer T-l in its position Thus the switch RV is transmitting wireless signals. adapted to short circuit selectively one of the transformers T-1 and T-Zsb that the set may operate selectively as a broadcasting radio or television receiver.

The anode a2 or the grid g-3 of the triode L-2 attached to the oscillator coil B is connected through a coupling condenser c with a control grid g-4 of a buffer tube L4 which is separate from the tubes L-1 and L-2. Said bufier tube L-4 is constituted by the association of two triodes and it includes a first group of triode electrodes c4-g-- la4, the through a condenser cp with forming part of the Patented Dec. 2s, 1 958 furthermore, an arrangement frequency for the execution of the above described method. Said arrangement is in-- tended for a combined wireless and television receiving. set including a high frequency wireless chain, leading toand modulating tubes of which.

of example in accompanying.

primaries of the con- T2, the primary of which is anode a4 of which is coupled the modulating grid g- S second gro p of triode electrodes acting'asa mixer: Thegrid g-S is fed furthermore by the television signals amplified inthe' high frequency stages the last stage of which includes the tuning circuit av. These telev sion signals are produced by the high frequency-systemshown-diagrammatically atM; while'ithefl high frequencyradio"signals"are furnished by'means'shown diagrammatically atNi i The anode a-S of the secon'd groupof' triodeelectrodes g5-a-5 is connected with a high voltage supply througha-ciicuit RLCtnnedto'theinterrnediate-frequency intended for television-purposes and produced by the change of" frequency performed" inside' the modulating tl'lbdg-Sfl-Si This intermediate: frequency alsocon tains the-sound components-ofthe television signals'and consequently there ;is provided a low-impedance coupling:

of the transformer T-l of the "sound components of the television'signals'tappedoffthrough said'turns'Sp: If the" audio and video signals of the television transmission are? not separateduponreception, the audio signals are trans: mittedto' the tube- L"3 tl1rough" said auxiliary circuit" S1zSr and the-secondaryof the transformer T l."

The anode circuit passing through the" anodefai of the frequency changing triode is coupled with "the intermediate" frequencystages MF-TV of the television signals;

The doubling of the frequency of.the fundamental waves produced by the local oscillating.' tubeL-2' is? obtainedin accordance with *a conventional procedureby the first triode c 4 g=4-'a-4: The"latter" formsia classB amplifying triode operating through a biasing of the cathode and a supplementary grid current bringin'gtlie" tube to cut-elf conditions' for rat-predetermined value'of the anode voltage. Consequently, the anodejcurretit lp" shows two'peaks respectively atlp and 1"12, saidpeaks being separated by adepression N, for each period'of't he alternating grid-voltage Vg. The frequency'ofthe fundamental waves corresponding to Vgis thus doubled in the '40 anode current; 1p (Fig; 2)

The buffer tube- L-4 which allows the passage" there: through of the 'fundameutalfrequencyproducesra frequency which is 'doublethat -of'the fundamental frequency at=a"leve1- higherthanthatf of the harmonic 2 of the 145 fundamental oscillation considered" alone. It is thus' pos sible to bring'saidharrnonic throughsuitable'biasingsteps' tar-the desired levelfor' its' rationaiusejin a" combined wireless and television" setdesigned*for" the irecepti'on of numerous --frequencyranges 'or'bands;

On the'other hand, the"incorporat1on"'of'this separate buffer stage; which cuts out the parasitical reactions between the local oscillations and the incoming signals remove-s any risk of a shifting'of the frequency insidefthe frequency range'to'be received:

In the second embodiment'illustrated'linFig; 3, I resort to-a' conventional frequency doubler'including twogrid anode groups I-II mounted in phase opposition""condi tions-inside a common buffer tube L-S. Iproduce'inside said frequency-doubling tube. a predetermined want of balance-so-as"toobtain'a highyield for the fundamental" wave. 3 This ;want of balance is produced" by means of a voltage-divider R'1--R-2 connecting the grids 'g7'-g-8 and adapted to make R-l different from R-2. The triode" L-6, the grid g-6 of which is coupled with the anode'v65 system 'a7--a-6 of'the-tube L-S serves as amodulator in the, manner. disclosed 'for'the second triode g5--a+5 in the, arraugementillustratedin Fig: 1. 1

Whatl claim iSZ'.

1. "Iii' a comhined wireless'radio and television set the" 7g provision of "a higlr' frequency radio amplifyingchain, at least, one oscillating and 'mojdula't'ing.tubeifed byg'said chains. including a. cathode; a modulating grid and'an anode, arlocalcoscillatiomproducing.1 tube' .energizing;said s modulating-grid" and iucludingg an; anode, ;at least. one .i *5

buffer system including a first group of electrodes constituted by a cathode; an anode and a grid fed by the" oscillations of the oscillation-producing tube, said first group of electrodes being adapted to double the frequency of the local oscillations, and a second group of electrodes constituted by a cathode, an anode and a control grid coupled with the anode of the first group, a high frequency television amplifying chain feedingthe control grid- 0f the second'group of electrodes in the buffer system to mix the television signals with the doubled local oscillations, and anintermediate television frequency chain fed by the anode of said second group.

2. In a-combined'wireless radio'and'television'seg the provision of a high frequency radio amplifying chain, at least one" oscillating and modulating tube fed" by" said" chain including a cathode, ajmodulating grid and an anode, a local oscillation-producing tube energizing said modulating grid and including an anode, at least one buffer system incliiding a double "tube adapted to dolil'ile the local frequency" andhaving" a cathode, two grids in sorted in phaseop'position to either side of thercatliode and fdf by tlie-'-'oseillati 1 1810 tube;'andtwo'anodes'associated'with'said grids an adjust ablevoltage divider connecting thesaid gridsofithe' don 32"Ii1 a' combined wireles'siadio and {television se the provision "ofa high frequency radio amplifyin'g' chain,

transformersfat least one'bufier system including a first group ofelectrodes constituted'byacathode, an anode anda'gridfedby'the oscillations of the'oscillation p'ro Z ducing tube, saidfi'rst group of electrodes being fadapted to doublethefrequency of theloc'al oscillations, and a firstgroup f a high frequency television "amplifying 1n feeding-the contfollg rid of the second group or ele c od'e 's i in the buffer syst'enijto mix the television signals ivi'th 'th doubled rocar os cillatirir'is, an intermediate "televisi" quency chainfed by the anode" of" 'saidfse'econd gr least onetu'rn fed by the anode" of"the-"secondfgr electrodes adapted to collect the intermediate television -sound components a lowimpedance coupl ng: line connected with said turns" an'dcoupledwith" one of least one oscillating and modulating tube fedbysaid chain and including a' cathodei 'a rifodulatinggridand an anode, a local oseillatiorr-producing=' tube "energizing said rno'dulating grid andineluding 'an' anode, transformers :'con-'" netted with 'the anode' of the oscillatingi and"modulating tube; a common intermediate frequency chain for t the wireless radio' and television sound signals fed by said 1* transformersg a double t be: adapted 'to "double'the local frequency and -includingla cathode; two grids insertedf in phase opposition to either side of the cathode and fed by the soscillations-of the oscillation-producing tube; and two.anodes r'associated--with+ said grids,- an adjustable voltage divider connecting the grids of said doubletube and adapted-iomodify the balance:of the double tube,

a furtherutubehaving-a grid connectedwith hoth anodes f" the" osclllatio nepr'oducing t apted to modif' the balance of thefdbuble" d connected with both" at" lea'st one os'cillating'and' modulating: tube fed by' said" chain including'a cathode, a'modulating grid: and an" ariodega local oscillation-producing tube energizing said modulating gridan'd including arr'anode, transformers" connected with the anode of the oscillating *and'modtilzit ing' tube, a"comm'onintermediate frequency chain forthe wirelessradio and television sound signals .fed by said" corribined"wireles s radio and"tele'vision*set the of the double tube and an anode, a high frequency television amplifying chain feeding the control grid of said further tube to mix the television signals with the doubled local oscillations, an intermediate television frequency chain fed by the anode of said further tube, and at least one convolution fed by the anode of the last mentioned tube adapted to collect the intermediate frequency television sound components, and a low impedance coupling line connected with said convolutions and coupled with one of the transformers to reinject the television sound signals into the said common intermediate frequency chain.

5. In a combined wireless radio and television set of the frequency band type, the combination of an oscillating and modulating tube, means for feeding said tube with the incoming amplified high frequency signals, a local oscillator including a grid connected with the tube to produce the intermediate radio frequency, an independent aperiodic buffer tube system fed with the output of the local oscillator including a first electrode group adapted to operate as a frequency doubler and a second electrode group adapted to be fed with the incoming television signals and to mix them with the multiplied frequency Waves from the first mentioned group to produce the intermediate television frequency an intermediate television frequency circuit fed thereby and circuits tuned to predetermined intermediate audio signal frequencies and fed with the output of the oscillating and modulating tube.

6. In a combined Wireless radio and television set of the frequency band type, the combination of an oscillating and modulating tube, means for feeding said tube with the incoming amplified high frequency signals, a local oscillator including a grid connected with the tube to produce the intermediate radio frequency, an independent buffer tube including in sequence a first cathode, a first grid fed by the output of the local oscillator, a first anode, a second cathode connected with the first cathode, a second grid, a condenser coupling between the second grid and the first anode and a second anode, the first cathode, grid and anode system operating as a frequency doubler, means feeding high frequency television signals to the second grid to mix the said television signals with the doubled local oscillator frequency, an intermediate television frequency circuit fed by said second anode and circuits tuned to predetermined intermediate audio signal frequencies and fed with the output of the oscillating and modulating tube.

7. In a combined wireless radio and television set of the frequency band type, the combination of an oscillating intermediate television frequency, an intermediate television frequency circuit fed thereby, circuits tuned to predetermined intermediate audio signal frequencies and fed with the output of the oscillating and modulating tube and a circuit including coils coupled respectively with one of the last mentioned circuits and with the intermediate television frequency circuit.

8. In a combined wireless radio and television set of the frequency band type, the combination of an oscillating and modulating tube, means for feeding said tube With the incoming amplified high frequency signals, a local oscillator including a grid connected with the tube to produce the intermediate radio frequency, an independent buffer tube including in sequence a first cathode, a first grid fed by the output of the local oscillator, a first anode, a second cathode connected with the first cathode, a second grid, a condenser coupling between the second grid and the first anode and a second anode, the first cathode, grid and anode system operating as a frequency doubler, means feeding high frequency television signals to the second grid to mix the said television signals with the doubled local oscillator frequency, an intermediate television frequency circuit fed by said second anode, circuits tuned to predetermined intermediate audio signal frequencies and fed with the output of the oscillating and modulating tube and a circuit including coils coupled respectively with one of last mentioned circuits and with the intermediate television frequency circuit.

References Cited in the file of this patent UNITED STATES PATENTS 

